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denoland-deno/cli/tools/test/channel.rs
Matt Mastracci 7cc584ed79
fix(cli): fix deadlock in test writer when test pipe is full (#23210)
The tests would deadlock if we tried to write the sync marker into a
pipe that was full because one test streamed just enough data to fill
the pipe, so when we went to actually write the sync marker we blocked
when nobody was reading.

We use a two-phase lock for sync markers now: one to indicate "ready to
sync" and the second to indicate that the sync bytes have been received.
2024-04-04 18:06:58 +00:00

692 lines
22 KiB
Rust

// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
use super::TestEvent;
use super::TestStdioStream;
use deno_core::futures::future::poll_fn;
use deno_core::parking_lot;
use deno_core::parking_lot::lock_api::RawMutex;
use deno_core::parking_lot::lock_api::RawMutexTimed;
use deno_runtime::deno_io::pipe;
use deno_runtime::deno_io::AsyncPipeRead;
use deno_runtime::deno_io::PipeRead;
use deno_runtime::deno_io::PipeWrite;
use std::fmt::Display;
use std::future::Future;
use std::io::Write;
use std::pin::Pin;
use std::sync::atomic::AtomicUsize;
use std::sync::atomic::Ordering;
use std::sync::Arc;
use std::task::ready;
use std::task::Poll;
use std::time::Duration;
use tokio::io::AsyncRead;
use tokio::io::AsyncReadExt;
use tokio::io::ReadBuf;
use tokio::sync::mpsc::error::SendError;
use tokio::sync::mpsc::UnboundedReceiver;
use tokio::sync::mpsc::UnboundedSender;
use tokio::sync::mpsc::WeakUnboundedSender;
/// 8-byte sync marker that is unlikely to appear in normal output. Equivalent
/// to the string `"\u{200B}\0\u{200B}\0"`.
const SYNC_MARKER: &[u8; 8] = &[226, 128, 139, 0, 226, 128, 139, 0];
const BUFFER_SIZE: usize = 4096;
/// The test channel has been closed and cannot be used to send further messages.
#[derive(Debug, Copy, Clone, Eq, PartialEq)]
pub struct ChannelClosedError;
impl std::error::Error for ChannelClosedError {}
impl Display for ChannelClosedError {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.write_str("Test channel closed")
}
}
impl<T> From<SendError<T>> for ChannelClosedError {
fn from(_: SendError<T>) -> Self {
Self
}
}
#[repr(transparent)]
struct SendMutex(*const parking_lot::RawMutex);
impl Drop for SendMutex {
fn drop(&mut self) {
// SAFETY: We know this was locked by the sender
unsafe {
(*self.0).unlock();
}
}
}
// SAFETY: This is a mutex, so it's safe to send a pointer to it
unsafe impl Send for SendMutex {}
/// Create a [`TestEventSenderFactory`] and [`TestEventReceiver`] pair. The [`TestEventSenderFactory`] may be
/// used to create [`TestEventSender`]s and stdio streams for multiple workers in the system. The [`TestEventReceiver`]
/// will be kept alive until the final [`TestEventSender`] is dropped.
pub fn create_test_event_channel() -> (TestEventSenderFactory, TestEventReceiver)
{
let (sender, receiver) = tokio::sync::mpsc::unbounded_channel();
(
TestEventSenderFactory {
sender,
worker_id: Default::default(),
},
TestEventReceiver { receiver },
)
}
/// Create a [`TestEventWorkerSender`] and [`TestEventReceiver`] pair.The [`TestEventReceiver`]
/// will be kept alive until the [`TestEventSender`] is dropped.
pub fn create_single_test_event_channel(
) -> (TestEventWorkerSender, TestEventReceiver) {
let (factory, receiver) = create_test_event_channel();
(factory.worker(), receiver)
}
/// Polls for the next [`TestEvent`] from any worker. Events from multiple worker
/// streams may be interleaved.
pub struct TestEventReceiver {
receiver: UnboundedReceiver<(usize, TestEvent)>,
}
impl TestEventReceiver {
/// Receive a single test event, or `None` if no workers are alive.
pub async fn recv(&mut self) -> Option<(usize, TestEvent)> {
self.receiver.recv().await
}
}
struct TestStream {
id: usize,
which: TestStdioStream,
read_opt: Option<AsyncPipeRead>,
sender: UnboundedSender<(usize, TestEvent)>,
}
impl TestStream {
fn new(
id: usize,
which: TestStdioStream,
pipe_reader: PipeRead,
sender: UnboundedSender<(usize, TestEvent)>,
) -> std::io::Result<Self> {
// This may fail if the tokio runtime is shutting down
let read_opt = Some(pipe_reader.into_async()?);
Ok(Self {
id,
which,
read_opt,
sender,
})
}
/// Send a buffer to the test event channel. If the channel no longer exists, shut down the stream
/// because we can't do anything.
#[must_use = "If this returns false, don't keep reading because we cannot send"]
fn send(&mut self, buffer: Vec<u8>) -> bool {
if buffer.is_empty() {
true
} else if self
.sender
.send((self.id, TestEvent::Output(self.which, buffer)))
.is_err()
{
self.read_opt.take();
false
} else {
true
}
}
fn is_alive(&self) -> bool {
self.read_opt.is_some()
}
/// Cancellation-safe.
#[inline]
fn pipe(&mut self) -> impl Future<Output = ()> + '_ {
poll_fn(|cx| self.poll_pipe(cx))
}
/// Attempt to read from a given stream, pushing all of the data in it into the given
/// [`UnboundedSender`] before returning.
fn poll_pipe(&mut self, cx: &mut std::task::Context) -> Poll<()> {
let mut buffer = [0_u8; BUFFER_SIZE];
let mut buf = ReadBuf::new(&mut buffer);
let res = {
// No more stream, we shouldn't hit this case.
let Some(stream) = &mut self.read_opt else {
unreachable!();
};
ready!(Pin::new(&mut *stream).poll_read(cx, &mut buf))
};
match res {
Ok(_) => {
let buf = buf.filled().to_vec();
if buf.is_empty() {
// The buffer may return empty in EOF conditions and never return an error,
// so we need to treat this as EOF
self.read_opt.take();
} else {
// Attempt to send the buffer, marking as not alive if the channel is closed
_ = self.send(buf);
}
}
Err(_) => {
// Stream errored, so just return and mark this stream as not alive.
_ = self.send(buf.filled().to_vec());
self.read_opt.take();
}
}
Poll::Ready(())
}
/// Read and "block" until the sync markers have been read.
async fn read_until_sync_marker(&mut self) {
let Some(file) = &mut self.read_opt else {
return;
};
let mut flush = Vec::with_capacity(BUFFER_SIZE);
loop {
let mut buffer = [0_u8; BUFFER_SIZE];
match file.read(&mut buffer).await {
Err(_) | Ok(0) => {
// EOF or error, just return. We make no guarantees about unflushed data at shutdown.
self.read_opt.take();
return;
}
Ok(read) => {
flush.extend(&buffer[0..read]);
if flush.ends_with(SYNC_MARKER) {
flush.truncate(flush.len() - SYNC_MARKER.len());
// Try to send our flushed buffer. If the channel is closed, this stream will
// be marked as not alive.
_ = self.send(flush);
return;
}
}
}
}
}
}
/// A factory for creating [`TestEventSender`]s. This factory must be dropped
/// before the [`TestEventReceiver`] will complete.
pub struct TestEventSenderFactory {
sender: UnboundedSender<(usize, TestEvent)>,
worker_id: AtomicUsize,
}
impl TestEventSenderFactory {
/// Create a [`TestEventWorkerSender`], along with a stdout/stderr stream.
pub fn worker(&self) -> TestEventWorkerSender {
let id = self.worker_id.fetch_add(1, Ordering::AcqRel);
let (stdout_reader, stdout_writer) = pipe().unwrap();
let (stderr_reader, stderr_writer) = pipe().unwrap();
let (sync_sender, mut sync_receiver) =
tokio::sync::mpsc::unbounded_channel::<(SendMutex, SendMutex)>();
let stdout = stdout_writer.try_clone().unwrap();
let stderr = stderr_writer.try_clone().unwrap();
let sender = self.sender.clone();
// Each worker spawns its own output monitoring and serialization task. This task will
// poll the stdout/stderr streams and interleave that data with `TestEvents` generated
// by the test runner worker.
//
// Note that this _must_ be a separate thread! Flushing requires locking coördination
// on two threads and if we're blocking-locked on the mutex we've sent down the sync_receiver,
// there's no way for us to process the actual flush operation here.
//
// Creating a mini-runtime to flush the stdout/stderr is the easiest way to do this, but
// there's no reason we couldn't do it with non-blocking I/O, other than the difficulty
// of setting up an I/O reactor in Windows.
std::thread::spawn(move || {
let runtime = tokio::runtime::Builder::new_current_thread()
.enable_io()
.build()
.unwrap();
runtime.block_on(tokio::task::unconstrained(async move {
let mut test_stdout = TestStream::new(
id,
TestStdioStream::Stdout,
stdout_reader,
sender.clone(),
)?;
let mut test_stderr =
TestStream::new(id, TestStdioStream::Stderr, stderr_reader, sender)?;
// This ensures that the stdout and stderr streams in the select! loop below cannot starve each
// other.
let mut alternate_stream_priority = false;
// This function will be woken whenever a stream or the receiver is ready
loop {
alternate_stream_priority = !alternate_stream_priority;
let (a, b) = if alternate_stream_priority {
(&mut test_stdout, &mut test_stderr)
} else {
(&mut test_stderr, &mut test_stdout)
};
tokio::select! {
biased; // We actually want to poll the channel first
recv = sync_receiver.recv() => {
match recv {
// If the channel closed, we assume that all important data from the streams was synced,
// so we just end this task immediately.
None => { break },
Some((mutex1, mutex2)) => {
// Two phase lock: mutex1 indicates that we are done our general read phase and are ready for
// the sync phase. mutex2 indicates that we have completed the sync phase. This prevents deadlock
// when the pipe is too full to accept the sync marker.
drop(mutex1);
for stream in [&mut test_stdout, &mut test_stderr] {
if stream.is_alive() {
stream.read_until_sync_marker().await;
}
}
drop(mutex2);
}
}
}
// Poll stdout first if `alternate_stream_priority` is true, otherwise poll stderr first.
// This is necessary because of the `biased` flag above to avoid starvation.
_ = a.pipe(), if a.is_alive() => {},
_ = b.pipe(), if b.is_alive() => {},
}
}
Ok::<_, std::io::Error>(())
}))?;
Ok::<_, std::io::Error>(())
});
let sender = TestEventSender {
id,
ref_count: Default::default(),
sender: self.sender.clone(),
sync_sender,
stdout_writer,
stderr_writer,
};
TestEventWorkerSender {
sender,
stdout,
stderr,
}
}
/// A [`TestEventWeakSender`] has a unique ID, but will not keep the [`TestEventReceiver`] alive.
/// This may be useful to add a `SIGINT` or other break handler to tests that isn't part of a
/// specific test, but handles the overall orchestration of running tests:
///
/// ```nocompile
/// let mut cancel_sender = test_event_sender_factory.weak_sender();
/// let sigint_handler_handle = spawn(async move {
/// signal::ctrl_c().await.unwrap();
/// cancel_sender.send(TestEvent::Sigint).ok();
/// });
/// ```
pub fn weak_sender(&self) -> TestEventWeakSender {
TestEventWeakSender {
id: self.worker_id.fetch_add(1, Ordering::AcqRel),
sender: self.sender.downgrade(),
}
}
}
pub struct TestEventWeakSender {
pub id: usize,
sender: WeakUnboundedSender<(usize, TestEvent)>,
}
impl TestEventWeakSender {
pub fn send(&mut self, message: TestEvent) -> Result<(), ChannelClosedError> {
Ok(
self
.sender
.upgrade()
.ok_or(ChannelClosedError)?
.send((self.id, message))?,
)
}
}
pub struct TestEventWorkerSender {
pub sender: TestEventSender,
pub stdout: PipeWrite,
pub stderr: PipeWrite,
}
/// Sends messages from a given worker into the test stream. If multiple clones of
/// this sender are kept alive, the worker is kept alive.
///
/// Any unflushed bytes in the stdout or stderr stream associated with this sender
/// are not guaranteed to be sent on drop unless flush is explicitly called.
pub struct TestEventSender {
pub id: usize,
ref_count: Arc<()>,
sender: UnboundedSender<(usize, TestEvent)>,
sync_sender: UnboundedSender<(SendMutex, SendMutex)>,
stdout_writer: PipeWrite,
stderr_writer: PipeWrite,
}
impl Clone for TestEventSender {
fn clone(&self) -> Self {
Self {
id: self.id,
ref_count: self.ref_count.clone(),
sender: self.sender.clone(),
sync_sender: self.sync_sender.clone(),
stdout_writer: self.stdout_writer.try_clone().unwrap(),
stderr_writer: self.stderr_writer.try_clone().unwrap(),
}
}
}
impl TestEventSender {
pub fn send(&mut self, message: TestEvent) -> Result<(), ChannelClosedError> {
// Certain messages require us to ensure that all output has been drained to ensure proper
// interleaving of messages.
if message.requires_stdio_sync() {
self.flush()?;
}
Ok(self.sender.send((self.id, message))?)
}
/// Ensure that all output has been fully flushed by writing a sync marker into the
/// stdout and stderr streams and waiting for it on the other side.
pub fn flush(&mut self) -> Result<(), ChannelClosedError> {
// Two phase lock: mutex1 indicates that we are done our general read phase and are ready for
// the sync phase. mutex2 indicates that we have completed the sync phase. This prevents deadlock
// when the pipe is too full to accept the sync marker.
let mutex1 = parking_lot::RawMutex::INIT;
mutex1.lock();
let mutex2 = parking_lot::RawMutex::INIT;
mutex2.lock();
self
.sync_sender
.send((SendMutex(&mutex1 as _), SendMutex(&mutex2 as _)))?;
if !mutex1.try_lock_for(Duration::from_secs(30)) {
panic!(
"Test flush deadlock 1, sender closed = {}",
self.sync_sender.is_closed()
);
}
_ = self.stdout_writer.write_all(SYNC_MARKER);
_ = self.stderr_writer.write_all(SYNC_MARKER);
if !mutex2.try_lock_for(Duration::from_secs(30)) {
panic!(
"Test flush deadlock 2, sender closed = {}",
self.sync_sender.is_closed()
);
}
Ok(())
}
}
#[cfg(test)]
mod tests {
use super::*;
use crate::tools::test::TestResult;
use deno_core::unsync::spawn;
use deno_core::unsync::spawn_blocking;
/// Test that output is correctly interleaved with messages.
#[tokio::test]
async fn spawn_worker() {
test_util::timeout!(60);
let (mut worker, mut receiver) = create_single_test_event_channel();
let recv_handle = spawn(async move {
let mut queue = vec![];
while let Some((_, message)) = receiver.recv().await {
let msg_str = format!("{message:?}");
if msg_str.len() > 50 {
eprintln!("message = {}...", &msg_str[..50]);
} else {
eprintln!("message = {}", msg_str);
}
queue.push(message);
}
eprintln!("done");
queue
});
let send_handle = spawn_blocking(move || {
worker.stdout.write_all(&[1; 100_000]).unwrap();
eprintln!("Wrote bytes");
worker.sender.send(TestEvent::StepWait(1)).unwrap();
eprintln!("Sent");
worker.stdout.write_all(&[2; 100_000]).unwrap();
eprintln!("Wrote bytes 2");
worker.sender.flush().unwrap();
eprintln!("Done");
});
send_handle.await.unwrap();
let messages = recv_handle.await.unwrap();
let mut expected = 1;
let mut count = 0;
for message in messages {
match message {
TestEvent::Output(_, vec) => {
assert_eq!(vec[0], expected);
count += vec.len();
}
TestEvent::StepWait(_) => {
assert_eq!(count, 100_000);
count = 0;
expected = 2;
}
_ => unreachable!(),
}
}
assert_eq!(expected, 2);
assert_eq!(count, 100_000);
}
/// Test that flushing a large number of times doesn't hang.
#[tokio::test]
async fn test_flush_lots() {
test_util::timeout!(240);
let (mut worker, mut receiver) = create_single_test_event_channel();
let recv_handle = spawn(async move {
let mut queue = vec![];
while let Some((_, message)) = receiver.recv().await {
assert!(!matches!(message, TestEvent::Output(..)));
queue.push(message);
}
eprintln!("Receiver closed");
queue
});
let send_handle = spawn_blocking(move || {
for _ in 0..100000 {
worker.sender.send(TestEvent::StepWait(1)).unwrap();
}
eprintln!("Sent all messages");
});
send_handle.await.unwrap();
let messages = recv_handle.await.unwrap();
assert_eq!(messages.len(), 100000);
}
/// Test that flushing a large number of times doesn't hang.
#[tokio::test]
async fn test_flush_large() {
test_util::timeout!(240);
let (mut worker, mut receiver) = create_single_test_event_channel();
let recv_handle = spawn(async move {
let mut queue = vec![];
while let Some((_, message)) = receiver.recv().await {
if let TestEvent::StepWait(..) = message {
queue.push(());
}
}
eprintln!("Receiver closed");
queue
});
let send_handle = spawn_blocking(move || {
for _ in 0..25000 {
// Write one pipe buffer's worth of message here. We try a few different sizes of potentially
// blocking writes.
worker.stderr.write_all(&[0; 4 * 1024]).unwrap();
worker.sender.send(TestEvent::StepWait(1)).unwrap();
worker.stderr.write_all(&[0; 16 * 1024]).unwrap();
worker.sender.send(TestEvent::StepWait(1)).unwrap();
worker.stderr.write_all(&[0; 64 * 1024]).unwrap();
worker.sender.send(TestEvent::StepWait(1)).unwrap();
worker.stderr.write_all(&[0; 128 * 1024]).unwrap();
worker.sender.send(TestEvent::StepWait(1)).unwrap();
}
eprintln!("Sent all messages");
});
send_handle.await.unwrap();
let messages = recv_handle.await.unwrap();
assert_eq!(messages.len(), 100000);
}
/// Test that flushing a large number of times doesn't hang.
#[tokio::test]
async fn test_flush_with_close() {
test_util::timeout!(240);
let (worker, mut receiver) = create_single_test_event_channel();
let TestEventWorkerSender {
mut sender,
stderr,
stdout,
} = worker;
let recv_handle = spawn(async move {
let mut queue = vec![];
while let Some((_, _)) = receiver.recv().await {
queue.push(());
}
eprintln!("Receiver closed");
queue
});
let send_handle = spawn_blocking(move || {
let mut stdout = Some(stdout);
let mut stderr = Some(stderr);
for i in 0..100000 {
if i == 20000 {
stdout.take();
}
if i == 40000 {
stderr.take();
}
if i % 2 == 0 {
if let Some(stdout) = &mut stdout {
stdout.write_all(b"message").unwrap();
}
} else if let Some(stderr) = &mut stderr {
stderr.write_all(b"message").unwrap();
}
sender.send(TestEvent::StepWait(1)).unwrap();
}
eprintln!("Sent all messages");
});
send_handle.await.unwrap();
let messages = recv_handle.await.unwrap();
assert_eq!(messages.len(), 130000);
}
/// Test that large numbers of interleaved steps are routed properly.
#[tokio::test]
async fn test_interleave() {
test_util::timeout!(60);
const MESSAGE_COUNT: usize = 10_000;
let (mut worker, mut receiver) = create_single_test_event_channel();
let recv_handle = spawn(async move {
let mut i = 0;
while let Some((_, message)) = receiver.recv().await {
if i % 2 == 0 {
let expected_text = format!("{:08x}", i / 2).into_bytes();
let TestEvent::Output(TestStdioStream::Stderr, text) = message else {
panic!("Incorrect message: {message:?}");
};
assert_eq!(text, expected_text);
} else {
let TestEvent::Result(index, TestResult::Ok, 0) = message else {
panic!("Incorrect message: {message:?}");
};
assert_eq!(index, i / 2);
}
i += 1;
}
eprintln!("Receiver closed");
i
});
let send_handle: deno_core::unsync::JoinHandle<()> =
spawn_blocking(move || {
for i in 0..MESSAGE_COUNT {
worker
.stderr
.write_all(format!("{i:08x}").as_str().as_bytes())
.unwrap();
worker
.sender
.send(TestEvent::Result(i, TestResult::Ok, 0))
.unwrap();
}
eprintln!("Sent all messages");
});
send_handle.await.unwrap();
let messages = recv_handle.await.unwrap();
assert_eq!(messages, MESSAGE_COUNT * 2);
}
#[tokio::test]
async fn test_sender_shutdown_before_receive() {
test_util::timeout!(60);
for _ in 0..10 {
let (mut worker, mut receiver) = create_single_test_event_channel();
worker.stderr.write_all(b"hello").unwrap();
worker
.sender
.send(TestEvent::Result(0, TestResult::Ok, 0))
.unwrap();
drop(worker);
let (_, message) = receiver.recv().await.unwrap();
let TestEvent::Output(TestStdioStream::Stderr, text) = message else {
panic!("Incorrect message: {message:?}");
};
assert_eq!(text.as_slice(), b"hello");
let (_, message) = receiver.recv().await.unwrap();
let TestEvent::Result(..) = message else {
panic!("Incorrect message: {message:?}");
};
assert!(receiver.recv().await.is_none());
}
}
/// Ensure nothing panics if we're racing the runtime shutdown.
#[test]
fn test_runtime_shutdown() {
test_util::timeout!(60);
let runtime = tokio::runtime::Builder::new_current_thread()
.enable_all()
.build()
.unwrap();
runtime.block_on(async {
let (mut worker, mut receiver) = create_single_test_event_channel();
tokio::task::spawn(async move {
loop {
if receiver.recv().await.is_none() {
break;
}
}
});
tokio::task::spawn(async move {
_ = worker.sender.send(TestEvent::Sigint);
});
});
}
}